In the semiconductor manufacturing process, as the photolithographic size is increasingly smaller, the resolution enhancement technique (RET) is widely adopted. In a case under the technology node of 180 nm, the OPC technology in RET is adopted as a conventional technical means. In the process of correction, two methods are usually adopted, one is the rule based OPC, another is the model based OPC (MBOPC); when the MBOPC manner is selected, the design pattern will be dissected into several relatively short segments, and target points of corresponding segments can be set. By way of introducing an edge placement error (EPE), i.e., the difference between the simulated value and the target value at the target point, so as to evaluate the result of each correction loop of the OPC. In the event the statistic values of the EPE of all segments reached a certain range, it is considered that the placement of all segments are completed; the placement process usually requires 3-8 rounds of repeated calculation, so as to ensure the statistic values of the EPE of all segments will reach a certain range.
In a conventional method of OPC, the placement location of the target points of the segments is relatively unchanged typically, such as setting to be the center or the end of each segment. Such a unchanged placement results in an insufficient adaptability to different patterns, whereby insufficient-correction or over-correction problems are caused, such that the correction is of low precision.